This invention relates to the field of phacoemulsification, and more particularly to drive circuits for phacoemulsification probes.
The use of ultrasonic handpieces or probes for the removal of cataracts in the human eye is well known. Typically, this procedure, called phacoemulsification, uses ultrasonic probes for rupturing cataracts in the eye, combined with aspiration of the resulting debris. Ultrasonic phacoemulsification probes conventionally include a piezoelectric crystal(s) affixed to a probe body. The crystal is driven by an electric power source and converts the electric power to ultrasonic power which is applied by the probe to the cataract.
The amount of power applied by the probe is a function of the frequency and amplitude of the driving electrical waveform and is typically under control of the surgeon using the probe. It is known that the frequency of the applied electrical waveform should be adjusted to the resonant frequency of the probe for efficient power conversion.
Prior art drive circuits for phacoemulsification probes function adequately, but they could be improved. For example, prior art drive circuits have a level of power consumption that is higher than desirable. This high level of power consumption is not only inefficient, it results in other deficiencies. Higher power consumption generates more heat, requiring the use of larger heat sinks than would be desirable, increasing the device's total weight and size, and, possibly, requiring additional cooling fans or other means of dissipating the excess heat.